A plan to build a private golf athletic facility and non-profit youth center on top of two parking garages in downtown Minneapolis moved forward today for the first time since it was proposed in 1998.

The Minneapolis Transportation and Public Works Committee on Tuesday approved rights to the developer, Downtown Rooftop Golf, LLC and Downtown Rooftop Youth Center to begin negotiations with the city and the Minnesota Department of Transportation to work out details on leasing the air space eight stories high.

Adjacent to Target Center, the two ramps are the city-owned Hawthorne Transportation Center, and the MnDOT-owned Seventh Street Third Avenue Distributor Ramp A.

The project is expected to cost between $70 million and $80 million and will be privately funded, along with grants for the non-profit portion, according to the committee’s report.

Elwyn Tinklenberg, a former state transportation commissioner working as a consultant on the project, said the first part of the project is the youth center, in the northwest area of the space.

“This is not incidental to the project, this is the heart and soul of this project,” Tinklenberg said to the committee at Tuesday’s meeting.

The center will provide space for classrooms, enrichment programming and mentorship, and will be located next to the for-profit athletic facilities centered around golf, for use by youth for sports and entertainment.

In the middle of the rooftop space, the golf entertainment center will include a driving range, indoor putting areas, simulators, conference space, performance area, club house and training facilities, locker rooms, food and beverage facilities, playing fields, and walking and running tracks.

“You’ve heard it described as a driving range — it’s much more than that,” Tinklenberg said.

Project staffers hope to put together details on design, partnerships, and financing in 2014, and start construction in 2015, Tinklenberg said. Construction is expected to last between 18 months and two years.

On the far end of the Hawthorne Ramp, the developer is proposing an outdoor green space and park performance area above the ramp.

Tinklenberg said the developer will partner with the University of Minnesota, Minneapolis Public Schools, and community groups to set up opportunities for youth in the facility. He said there will be a large indoor play area for soccer, lacrosse, field hockey, archery — “anything else you can imagine.”

The space will be flexible to accommodate as many activities as possible, Tinklenberg added.

The project had been stuck for about 15 years while the city and MnDOT worked on a way to allow lease of the space above the ramps.

“After so many years of trying unsuccessfully to get control of this site, now we can move forward,” Tinklenberg said.